Copper and dark oak contrast well to create a natural, mystical, and slightly sombre tone; similar to the tone of The Tale of the Three Brothers. I made this pendant using all scrap parts, some scrap oak and left over copper from some heavy duity electrical cables. The oak was cut by CNC router and the copper inlaid by hand, I know that not everyone has access to a CNC machine so I also devised a method for making this with a dremel or other small hand router.
I will explain in this section the procedure for CNC production as it is rather simple and most people who operate CNC equipment have their own preferred methodology and g-code production tools. The next section will explain a Non-CNC method for creating the wooden shape, and the final section will cover the basics of copper inlay.
CNC method - (Skip ahead for a Non-CNC method)
To make this pendant with a CNC router you should first download the attached .SVG file. This contains the vector for the pendant at the correct size, but you may wish to scale the size if you want. I generated the g-code using the free web-based CAM program MakerCAM.com. Simply upload the SVG to MakerCAM and start creating tool paths. I started by creating pocket operations for the small holes, using a pocket takes a bit longer but eliminates the problem of having loose small bits of wood that are difficult to hold down. I used a very fine endmill for this and used a rather conservative feed rate as to not snap the tiny bit.
Next I swapped out the bit for a slightly larger 1.5 mm endmill. I used a 1.5 mm bit because that is the diameter of the copper wire I had; making sure the copper wire thickness matches the cutting bit diameter fairly closely saves some frustration later. I then generated a "follow-path" operation for the lines where the copper is to be inlaid. The depth of this cut was also the diameter of the copper wire.
Following this, I used the same bit to cut out the final shape using an outside profile operation, tabs were also added to prevent the work from flying off. Now with the pendant cut, some sanding was needed to remove the tabs and generally smooth out the work, it was now ready for copper inlay.
Step 1: Non-CNC Method
The wood may also be cut without a CNC machine, with some careful and clever use of a dremel with a router attachment. For this you will need the following:
Your work piece - You can see the oak I used for the CNC method still has enough space for another pendant.
Two scrap pieces of thin plywood - (only one shown) Got some 3mm scrap there, the larger the better.
Some straight edge scraps - I have a couple of 9mm plywood scraps with straight edges
Spray glue - not shown in the photo :(
A print out of the pendant template - You can download the .PNG file here of the .SVG file from the previous section.
Dremel tool - You'll also need a router attachment that allows accurate height adjustments.
Cutting tool - I have here a 1.5 mm endmill.
Wood screws - Not too long, about 15mm
Scroll saw, or Coping saw - Not shown :( A scroll saw is quicker but a coping saw is cheaper.
Step 2: Make a Hole
The first step of the Non-CNC method is to make a hole in the thin 3mm scrap plywood. It doesn't have to be a neat hole, just large enough for the whole of the template design to be seen through it. I cut this free-hand using the dremel. Next you'll want to fix the template to the work piece with some spray glue. Finally, make a sandwich...A wood sandwich. Using some of the screws, fix the scrap plywood to the work piece placing the screws as far from the work area as possible.
Step 3: Non-CNC Method - Continued
Next you will cut the trench in which the copper wire will reside, we will do this by cutting each straight line independently and then changing tactic for the circle. First, set your dremel to rest on the scrap plywood with the cutting tip just touching the template. Now we will bring in one of the 9mm straight edges and place it touching the router guard of the dremel as shown in the photo. Next, run the cutting tip up and down the template line making adjustments to the position of the 9mm plywood until the cutting tool follows the template line every time. It sometimes helps to use one screw on the 9mm plywood to use as a pivot point when making adjustments, use a second screw to lock it in position.
Once you have set up your plywood guide, lower the cutting tool by 1.5 mm and cut one side of the triangle. Repeat this process for each of the straight cuts. Cutting the circle is a little more tricky.
Enter the scroll saw (or coping saw). To make a circular guide we will cut a round hole into the second piece of 3mm scrap plywood. The diameter of this hole will depend on the size of your router guard so I can't give you an exact value. The radius can be worked out by adding together the radius of the template circle and the radius of the router guard (if your guard isn't round like mine is, then you will use the distance from the cutting tip to the edge you use to rest against a guide). Adding these values give the guide radius and doubling that gives the diameter. Use a compass to draw a circle on the scrap plywood with this diameter and cut it out with a scroll saw or coping saw. Place your new circular guide on your work, find the ideal location for it and secure it down. Now carefully route out the circle.
Now that we have cut the grooves for the copper we can do away with all the plywood and cut the holes. For this you can use a scroll saw (or coping saw) with a fine blade. Drill a small hole and thread the blade through this, now carefully follow the guide to cut the holes.
Finally you will need to cut the whole thing out, again you can use a scroll saw or coping saw to do this.
Step 4: Copper Inlay
As mentioned earlier, the copper was from some scrap heavy duty electrical cables. I simply stripped off the plastic sleeve and it was ready to go! You will also need a few other things to inlay the copper which I have listed below:
Copper wire - 'nuf said
Something round - I just happened to find this "tubular make-up product" which had roughly the right diameter
Flat file - This is useful for shaping the ends and is also needed to make the inlay flush to the wood.
AC glue - Bonds skin in seconds :D
Start by cutting 3 equal lengths for the triangle, you can use a print out of the template to get the lengths correct. The 4th straight piece is slightly shorter. For the circle, I found it easiest to wrap the with around a round object of roughly the right diameter, then make one cut where the wire overlaps, as shown in the photo. Once cut you can make small adjustments to get the pieces to fit together. Use the file to shape the ends so they fit together well, if you take your time with this they can fit together so well that it is difficult to see the join.
Once you have all your copper pieces, simply glue them into their grooves using AC glue. The glue will bond your fingers faster than it can bond the copper and wood, so it helps to use something metal like tweezers to manipulate the copper into place and save your fingers.
Step 5: Finishing
Once you have glued all the copper in place and given it some time to dry, you can use the file to level the copper flush to the wood. Carefully file away the copper paying attention not to file the wood too much, you should be able to feel when the file starts filing wood and copper instead of just copper.
Finally, drill a small hole through the top of the triangle to thread a cord through. You can also finish the pendant with some enamel or something, but it looks pretty awesome without a finish.
Second Prize in the